Carbon monoxide (CO) is a poisonous gas that is colorless, odorless, tasteless, and non-irritating. When inhaled, CO combines with the blood and prevents it from absorbing oxygen. When this oxygen-deficient blood reaches the heart and brain, it can damage those organs and cause illness or death.

How can I tell if CO is present?

There are several physical symptoms of CO poisoning, which vary depending on the amount of CO in the bloodstream (the higher the concentration, the greater the danger). Additionally, signs of CO present in a building can include unusually high indoor humidity with persistent heavy condensation on walls and windows, stuffy or stale indoor air, and soot or water collecting near a burner or vent.

Physical signs of exposure

Mild
exposure:

Medium
exposure:

Severe
exposure:

Slight headache

Drowsiness

Convulsions

Vomiting

Confusion

Unconsciousness

Nausea

Severe headache

Cardiac/respiratory arrest

Fatigue

Rapid heart rate

Even death

Blurred Vision

Flu-like symptoms that disappear when the person breaths fresh air

Severity of the physical symptoms will vary depending on age, general health, level of physical activity, and duration and concentration of exposure.

What is the treatment for CO poisoning?

Treat with fresh air or pure oxygen.

Severe exposure requires medical attention.

What are the sources of CO?

Usually CO is produced while burning fuels like gasoline, coal, wood, charcoal, kerosene, natural gas, propane and heating oil, as well as almost any other combustible material such as tobacco, fibers or paper. There is an even greater risk of CO accumulation if your home or building is tightly sealed and not properly ventilated. While smoke inhalation from fires is a common cause of CO poisoning, cigarette smoke and vehicle exhaust are the most common sources of CO exposure.

If your home or building has an attached or tucked-under garage, air and any pollutants in the air may flow from the garage into the structure. So, if you leave a car or other combustion engine running inside the garage, or if an air intake duct is located next to a heavily traveled road or near a loading dock, CO can accumulate.

Any fuel-burning equipment or appliances, including wood stoves, fireplaces, space heaters, barbecue grills, furnaces, water heaters, boilers and ranges, have the potential to produce CO. When natural gas equipment is properly operated and maintained, it usually will not produce CO.

Why does CO accumulate and not escape through the chimney?

CO usually forms when fuel-burning appliances and equipment are malfunctioning or improperly maintained. Normally, when adequate combustion air is available and the appliance is properly installed and maintained, all gases and other combustion by-products will be harmlessly vented to the outdoors.

Homes and other buildings that are tightly sealed or have large exhaust systems, such as kitchen exhaust fans, need a system that provides air to replace the air that is pulled out by the exhaust. Without adequate make-up air, air from the outside can be pulled down a chimney and cause CO to form.

What do I do if I suspect CO is present?

Open windows to ventilate the area.

Shut off your furnace and other fuel-burning appliances.

If you're experiencing physical symptoms, get everyone, including pets, out of your home or building.

If CO is discovered, don't return to your home or building until the source is found and the problem corrected.

If I smell natural gas, is that the same as CO?

No. CO has no smell. When you smell natural gas, you smell an odorant we add to natural gas for safety reasons. If you smell natural gas, leave your home immediately and call CenterPoint Energy from another location.

How do I prevent CO buildup?

Never operate an automobile, lawn mower or any combustion engine, or barbecue grill or similar equipment, in an enclosed area such as your home, garage, tent, trailer or place of business, even with the door open.

Check frequently for visible signs of problems, such as high indoor humidity, or soot or water collecting near a burner or vent.

Equipment that uses natural gas should produce a clear blue flame. A yellow or orange flame may indicate a problem, and equipment should be checked by a qualified technician.

Provide adequate combustion air for all your appliances by avoiding too many appliances vented to one vent pipe.

Make sure your fresh air intake(s) is unobstructed.

Be certain all fuel-burning appliances and equipment are properly vented to the outdoors.

Keep vents and chimneys clear of debris or other obstruction and check for vent pipes that have gaps, leaks, spaces, or are rusted through.

If you use a gas space heater that is unvented, leave a nearby window open at least an inch to allow fresh air to enter the room.

Have your gas central heating unit checked before the heating season begins to make sure the heat exchanger is not cracked or rusted and that the burner area is clean.

Never attempt to heat a room with a natural gas range, oven or clothes dryer.

If you have equipment converted from one type of fuel to another, have the conversion done by a qualified technician. You can purchase a CO detection device with an audible alarm and a digital display, installed near bedrooms, that can provide added protection. Make sure it is IAS-6-96 approved or meets the Underwriters Laboratories Standard 2034. Look for the "UL" stamp on the box, and carefully follow the manufacturer's directions for operation, placement and maintenance.